my 914 1.7L is all oe and I've done a lot of work to it. i replaced a lot of parts and now i cant get my idle to 975 or so it seems to stay at 1800 whats the deal anyone know? i have adjusted and adjusted, i cant get it!???
Thanks andrew

Andrew,

I'm not too much help, but I think you can get a lot of info if you search "vacuum leak".

Good luck.


Warrenoliver

Sounds like you got a air leak somewhere on the intake side ...
Andy

also

Rich

thanks man, i do think its a vacuum leak! is there an easier way to find the bad boy or is it check till i find it?

one Djet.
Unplug every vacuum line and plug it.
Only leave the MPS plugged into the plenum.

You dont need any other lines to run.
Common leaks are at the AAR valve, and the rubber "Y" fitting for both that and the decel valve.

Add them back one at a time till you find the issue.
Sometimes the AAR valve gets stuck open and that creates a pretty large leak.

Rich

At your own risk you can use something like ether SPARINGLY around all the suspect places metioned above.

I've had the same issue for 4 years. It idles about 1500 (cold) until it warms up,(HOT) then it drops to about 700. BTW it seems to lose about 25% of it's power/torque when it gets that hot. I think the cold start valve helps with the power.

Cold start valve just injects extra fuel IF the temps are VERY cold (like near freezing).

Things that can cause high idle on DJet:

1. Vacuum leak below throttle's butterfly.
2. Throttle butterfly not closing squarely.
3. Overly advanced timing.

Sometimes tracing the vacuum leak can be a pain, but it most certainly can be a simple and methodical process because there are only so many potential sources between the butterfly and the heads, so follow the path....

-Injector seals (2 per injector)
-Phenolic block between heads and intake runners
-Rubber boots between intake runners and plenum
-Crack in plenum (usually around vertical reinforcement tubes)
-Gasket between plenum and throttle body
-Excess wear around butterfly pivots
-Air bypass / idle adjust screw in throttle body
-Any vacuum tap on plenum or throttle body below butterfly. (Some of those taps have to be traced upstream to parts that can cause the problem, like the AAR. But on Djet, you can just pull the hose and plug the hole like Rich said to help troubleshoot most of those.)

Your AAR is what makes it idle higher when cold and then settle to 700 when hot.
700 is to low btw. It supposed to do that..its like a choke.
The AAR adds more air when cold and this makes the motor run faster...

Your AAR may be leaking and not sealing up when closed..

Rich